According to one approach, beamformers utilize phase shifters or active true time delay modules. As opposed to beamformers utilizing phase shifters, beamformers utilizing active TTD modules are able to steer and maintain a beam's position independent of frequency, thereby avoiding undesirable beam “squint.”.
Active TTD modules, however, tend to experience two serious disadvantages when compared to phase shifters. First, active TTD modules tend to have higher insertion loss when implemented with MMIC technologies, as a result of their higher line RF losses. Second, due to these higher line losses, the loss imbalance between the various TTD states can vary considerably with frequency, requiring frequency-dependent amplitude imbalance correction for each state and the concomitant extra electronics needed to correct these issues within an array beamformer. The performance and cost impacts due to these issues usually renders active TTD modules impracticable for use in phased array architectures.
The present invention overcomes these limitations and deficiencies and provides other advantages as well.